Faculty Bibliography
Searched for:
in-biosketch:yes
person:cd38
Total Results:
237
Identification and characterization of Nasonia Pax genes
Pax genes are a group of critical developmental transcriptional regulators in both invertebrates and vertebrates, characterized by the presence of a paired DNA-binding domain. Pax proteins also often contain an octapeptide motif and a C-terminal homeodomain. The genome of Nasonia vitripennis (Hymenoptera) has recently become available, and analysis of this genome alongside Apis mellifera allowed us to contribute to the phylogeny of this gene family in insects. Nasonia, a parasitic wasp, has independently evolved a similar mode of development to that of the well-studied Drosophila, making it an excellent model system for comparative studies of developmental gene networks. We report the characterization of the seven Nasonia Pax genes. We describe their genomic organization, and the embryonic expression of three of them, and uncover wider conservation of the octapeptide motif than previously described.
PMCID:2852259
PMID: 20167022
ISSN: 1365-2583
CID: 1695012
Binary fate decisions in differentiating neurons
Neural cell fate programs must generate an enormous number of neurons with distinct adult functions. The decision to choose one neuronal subtype from two alternatives--a binary fate decision--is one way to diversify neuronal subtypes during nervous system development. Recent progress has been made in describing the genetic programs that define late-stage neuronal identity. Here, we review mechanisms that control how such fate decisions generate two different postmitotic, terminally differentiated neuronal subtypes. We survey examples from Caenorhabditis elegans and Drosophila that demonstrate different modes of binary neuronal fate specification that depend on cell division, lineage, stochastic gene expression, or extracellular signals. Comparison of these strategies reveals that, although organisms use diverse approaches to generate neural diversity, some common themes do exist.
PMCID:2827633
PMID: 20022236
ISSN: 1873-6882
CID: 1694552
Functional and evolutionary insights from the genomes of three parasitoid Nasonia species
We report here genome sequences and comparative analyses of three closely related parasitoid wasps: Nasonia vitripennis, N. giraulti, and N. longicornis. Parasitoids are important regulators of arthropod populations, including major agricultural pests and disease vectors, and Nasonia is an emerging genetic model, particularly for evolutionary and developmental genetics. Key findings include the identification of a functional DNA methylation tool kit; hymenopteran-specific genes including diverse venoms; lateral gene transfers among Pox viruses, Wolbachia, and Nasonia; and the rapid evolution of genes involved in nuclear-mitochondrial interactions that are implicated in speciation. Newly developed genome resources advance Nasonia for genetic research, accelerate mapping and cloning of quantitative trait loci, and will ultimately provide tools and knowledge for further increasing the utility of parasitoids as pest insect-control agents.
PMCID:2849982
PMID: 20075255
ISSN: 1095-9203
CID: 1694562
Dissecting and staining Drosophila optic lobes
Cold Spring Harbor, N.Y. : Cold Spring Harbor Laboratory Press, c2010
pp. 157-160
ISBN: 0879699051
CID: 1700012
Annual review of cell & developmental biology. 2010:26:689-719.DOI: 10.1146/annurev-cellbio-100109-104113
Stochastic mechanisms of cell fate specification that yield random or robust outcomes
Although cell fate specification is tightly controlled to yield highly reproducible results and avoid extreme variation, developmental programs often incorporate stochastic mechanisms to diversify cell types. Stochastic specification phenomena are observed in a wide range of species and an assorted set of developmental contexts. In bacteria, stochastic mechanisms are utilized to generate transient subpopulations capable of surviving adverse environmental conditions. In vertebrate, insect, and worm nervous systems, stochastic fate choices are used to increase the repertoire of sensory and motor neuron subtypes. Random fate choices are also integrated into developmental programs controlling organogenesis. Although stochastic decisions can be maintained to produce a mosaic of fates within a population of cells, they can also be compensated for or directed to yield robust and reproducible outcomes.
PMCID:3025287
PMID: 20590453
ISSN: 1530-8995
CID: 1694572
The twin spot generator for differential Drosophila lineage analysis
In Drosophila melanogaster, widely used mitotic recombination-based strategies generate mosaic flies with positive readout for only one daughter cell after division. To differentially label both daughter cells, we developed the twin spot generator (TSG) technique, which through mitotic recombination generates green and red twin spots that are detectable after the first cell division as single cells. We propose wide applications of TSG to lineage and genetic mosaic studies.
PMCID:2720837
PMID: 19633664
ISSN: 1548-7105
CID: 1694582
Heads and tails: evolution of antero-posterior patterning in insects
In spite of their varied appearances, insects share a common body plan whose layout is established by patterning genes during embryogenesis. We understand in great molecular detail how the Drosophila embryo patterns its segments. However, Drosophila has a type of embryogenesis that is highly derived and varies extensively as compared to most insects. Therefore, the study of other insects is invaluable for piecing together how the ancestor of all insects established its segmented body plan, and how this process can be plastic during evolution. In this review, we discuss the evolution of Antero-Posterior (A-P) patterning mechanisms in insects. We first describe two distinct modes of insect development - long and short germ development - and how these two modes of patterning are achieved. We then summarize how A-P patterning occurs in the long-germ Drosophila, where most of our knowledge comes from, and in the well-studied short-germ insect, Tribolium. Finally, using examples from other insects, we highlight differences in patterns of expression, which suggest foci of evolutionary change.
PMCID:2700975
PMID: 18976722
ISSN: 0006-3002
CID: 1694592
Maintaining a stochastic neuronal cell fate decision [Comment]
Sensory systems generally contain a number of neuronal subtypes that express distinct sensory receptor proteins. This diversity is generated through deterministic and stochastic cell fate choices, while maintaining the subtype often requires a distinct mechanism. In a study published in the February 1, 2009, issue of Genes & Development, Lesch and colleagues (pp. 345-358) describe a new transcription factor, NSY-7, that acts to stabilize a stochastic subtype choice in AWC chemosensory neurons in Caenorhabditis elegans.
PMCID:3959998
PMID: 19240127
ISSN: 1549-5477
CID: 1694602
Switch of rhodopsin expression in terminally differentiated Drosophila sensory neurons
Specificity of sensory neurons requires restricted expression of one sensory receptor gene and the exclusion of all others within a given cell. In the Drosophila retina, functional identity of photoreceptors depends on light-sensitive Rhodopsins (Rhs). The much simpler larval eye (Bolwig organ) is composed of about 12 photoreceptors, eight of which are green-sensitive (Rh6) and four blue-sensitive (Rh5). The larval eye becomes the adult extraretinal 'eyelet' composed of four green-sensitive (Rh6) photoreceptors. Here we show that, during metamorphosis, all Rh6 photoreceptors die, whereas the Rh5 photoreceptors switch fate by turning off Rh5 and then turning on Rh6 expression. This switch occurs without apparent changes in the programme of transcription factors that specify larval photoreceptor subtypes. We also show that the transcription factor Senseless (Sens) mediates the very different cellular behaviours of Rh5 and Rh6 photoreceptors. Sens is restricted to Rh5 photoreceptors and must be excluded from Rh6 photoreceptors to allow them to die at metamorphosis. Finally, we show that Ecdysone receptor (EcR) functions autonomously both for the death of larval Rh6 photoreceptors and for the sensory switch of Rh5 photoreceptors to express Rh6. This fate switch of functioning, terminally differentiated neurons provides a novel, unexpected example of hard-wired sensory plasticity.
PMCID:2750042
PMID: 18594514
ISSN: 1476-4687
CID: 1694612
